Claude Fable 5
Save 72%Officialanthropic/claude-fable-5
The previous Fable flagship — Mythos-class, above Opus.
- Context window
- 1M
- Max output
- 8K
- Input modalities
- text · image
- Output modalities
- text
- Capabilities
- Vision · Reasoning · Tool calling · Coding · Prompt cache · Strip Sampling Params
- Upstream release
- 2026-06-09
- RouteMux name
- anthropic/claude-fable-5
Try Claude Fable 5 here
Tune the request, see the current price ceiling, and inspect the real response without leaving this model page.
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What is Claude Fable 5
Claude Fable 5 is the previous flagship of Anthropic's Fable line — a Mythos-class model built for autonomous coding, sustained knowledge work, and agents that need to stay coherent over a long horizon. It carries a 1M-token context window with native prompt caching and vision input.
Through RouteMux it is $2.80 per 1M input tokens against Anthropic's $10, and $14 against $50 on output. Same model, same Anthropic Messages API, billed from a prepaid wallet instead of an Anthropic account, with failed and timed-out requests not charged.
It has been succeeded by Claude Fable 5.1, which costs the same per input and output token but reads from cache at $0.07 per 1M tokens against $0.28 here. New projects should start on 5.1; this page stays for callers already running on Fable 5.
Fable sits above Opus 5 in the lineup and costs twice as much per token, so the honest way to choose between them is to try Opus 5 first. Fable earns its price on tasks where a partially-correct answer is worthless — long refactors that must not leave stubs, analysis where a missed detail invalidates the conclusion.
Claude Fable 5 API pricing
Source: anthropic_x0.28 · Verified 2026-08-16
Cache read $0.28/M · Cache write $3.5/M
Estimate cost
Limited time20% extra Credits on your first top-up — up to 200 bonus Credits
Applies to your first top-up within 72 hours of signing up. Minimum $20, once per account.
Key capabilities
Previous Fable flagship
Anthropic's flagship tier for autonomous coding and long-horizon work, now succeeded by Fable 5.1. This tier remains in service.
1M-token context with caching
Native prompt caching, which matters more here than on cheaper models because the base rate is what caching discounts.
Vision input
Images go in the same message as the prompt — screenshots, diagrams, scanned documents.
Anthropic Messages native
No translation layer; the request is the same one you would send to Anthropic directly.
Interface and protocols
Use any of these IDs to call this model via the API.
anthropic/claude-fable-5Replace the ROUTEMUX_KEY placeholder with your API key. Create one →
from anthropic import Anthropic
client = Anthropic(
base_url="https://api.routemux.com/anthropic",
api_key="<ROUTEMUX_KEY>",
)
message = client.messages.create(
model="anthropic/claude-fable-5",
max_tokens=1024,
messages=[{"role": "user", "content": "What is the meaning of life?"}],
)
print(message.content[0].text)Performance (last 30 days)
Claude Fable 5 FAQ
›What is Claude Fable 5?
The previous Fable flagship — Mythos-class, above Opus.
›How large is the context window of Claude Fable 5?
Claude Fable 5 supports a context window of up to 1M tokens, with up to 8K output tokens per request.
›How much does the Claude Fable 5 API cost?
Through RouteMux, Claude Fable 5 costs $2.8 for input and $14 for output (USD per 1M tokens), below the official list price.
›How do I call Claude Fable 5 via API?
Claude Fable 5 is OpenAI-compatible: point your base URL at RouteMux and set the model field to anthropic/claude-fable-5 — no code changes needed.
›Which input and output modalities does Claude Fable 5 support?
Claude Fable 5 accepts text, image as input and produces text as output.
›When was Claude Fable 5 released?
Claude Fable 5 was released on June 9, 2026.
›How is Fable 5 different from Opus 5?
Fable is positioned above Opus in Anthropic's lineup and costs twice as much per token here ($2.80 vs $1.40 input). Both have a 1M context and the same capability set, so the difference is answer quality on hard tasks, not capacity.
›Is this the same Fable 5 as Anthropic's?
Yes — same model and same Messages API surface. RouteMux forwards the request and bills your prepaid wallet.
Sources
Reviewed by Jerry Fan on 2026-09-02